In order to examine arrest rate changes of drug patients after their participation in drug abuse rehabilitation programs, the present study analyzes interview reports and official arrest records of 772 patients who participated in the Illinois Drug Abuse Program, a methadone-centered multi-modality program. The data indicate that arrest rates among the sample have dropped significantly during their participation in the Program. The reduction rate, based on self- reported data, is 43 per cent. The reduction rate, based on the official arrest records, is 62 per cent. The official arrest record study shows further that the reduction of arrest rate is greatest for vice crimes, second greatest for narcotics offenses, and third greatest for prop erty crimes.